Pcbnew: Fix issue when flipping a graphic segment (SHAPE_T::SEGMENT).

PCB_SHAPE::Normalize() normalized a graphic segment by (sometimes) swapping
start and end points. But it creates an issue when flipping a segment: the
reference point can be changed.
This normalization was made for DRC purpose when comparing 2 footprints.
Now, PCB_SHAPE::Normalize() does not change end points of a segment, and a
specific PCB_SHAPE::NormalizeForCompare() normalize fct is used for DRC compare.

include/board_item.h

@@ -367,6 +367,13 @@ public:
      */
     virtual void Normalize() {}
 
+    /**
+     * Perform any normalization required to compare 2 graphics, especially
+     * if the can be rotated and/or flipped.
+     * Similar to Normalize(), but more changes can be made
+     */
+    virtual void NormalizeForCompare() { Normalize(); }
+
     /**
      * Return the #BOARD in which this #BOARD_ITEM resides, or NULL if none.
      */

pcbnew/drc/drc_test_provider_library_parity.cpp

@@ -562,7 +562,7 @@ bool FOOTPRINT::FootprintNeedsUpdate( const FOOTPRINT* aLibFP, int aCompareFlags
         temp->SetPosition( GetPosition() );
 
     for( BOARD_ITEM* item : temp->GraphicalItems() )
-        item->Normalize();
+        item->NormalizeForCompare();
 
     // This temporary footprint must not have a parent when it goes out of scope because it
     // must not trigger the IncrementTimestamp call in ~FOOTPRINT.
@@ -689,7 +689,7 @@ bool FOOTPRINT::FootprintNeedsUpdate( const FOOTPRINT* aLibFP, int aCompareFlags
     dummy.SetParent( nullptr );
 
     for( BOARD_ITEM* item : dummy.GraphicalItems() )
-        item->Normalize();
+        item->NormalizeForCompare();
 
     std::set<BOARD_ITEM*, FOOTPRINT::cmp_drawings> aShapes;
     std::copy_if( dummy.GraphicalItems().begin(), dummy.GraphicalItems().end(),

pcbnew/pcb_shape.cpp

@@ -479,22 +479,7 @@ void PCB_SHAPE::Scale( double aScale )
 
 void PCB_SHAPE::Normalize()
 {
-    if( m_shape == SHAPE_T::SEGMENT )
-    {
-        // we want start point the top left point and end point the bottom right
-        // (more easy to compare 2 segments: we are seeing them as equivalent if
-        // they have the same end points, not necessary the same order)
-        VECTOR2I start = GetStart();
-        VECTOR2I end = GetEnd();
-
-        if( ( start.x > end.x )
-            || ( start.x == end.x && start.y < end.y ) )
-        {
-            SetStart( end );
-            SetEnd( start );
-        }
-    }
-    else if( m_shape == SHAPE_T::RECTANGLE )
+    if( m_shape == SHAPE_T::RECTANGLE )
     {
         VECTOR2I start = GetStart();
         VECTOR2I end = GetEnd();
@@ -551,6 +536,28 @@ void PCB_SHAPE::Normalize()
 }
 
 
+void PCB_SHAPE::NormalizeForCompare()
+{
+    if( m_shape == SHAPE_T::SEGMENT )
+    {
+        // we want start point the top left point and end point the bottom right
+        // (more easy to compare 2 segments: we are seeing them as equivalent if
+        // they have the same end points, not necessary the same order)
+        VECTOR2I start = GetStart();
+        VECTOR2I end = GetEnd();
+
+        if( ( start.x > end.x )
+            || ( start.x == end.x && start.y < end.y ) )
+        {
+            SetStart( end );
+            SetEnd( start );
+        }
+    }
+    else
+        Normalize();
+}
+
+
 void PCB_SHAPE::Rotate( const VECTOR2I& aRotCentre, const EDA_ANGLE& aAngle )
 {
     rotate( aRotCentre, aAngle );

pcbnew/pcb_shape.h

@@ -125,6 +125,13 @@ public:
 
     void Normalize() override;
 
+    /**
+     * Normalize coordinates to compare 2 similar PCB_SHAPES
+     * similat to Normalize(), but also normalize SEGMENT end points
+     * needed only for graphic comparisons
+     */
+    void NormalizeForCompare() override;
+
     void Move( const VECTOR2I& aMoveVector ) override;
 
     void Rotate( const VECTOR2I& aRotCentre, const EDA_ANGLE& aAngle ) override;